On 07/22/2013 06:21 PM, Christoffer Dall wrote: > On 22 July 2013 10:53, Raghavendra KT <raghavendra.kt.linux@xxxxxxxxx> wrote: >> On Fri, Jul 19, 2013 at 7:23 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>> So far, when a guest executes WFE (like when waiting for a spinlock >>> to become unlocked), we don't do a thing and let it run uninterrupted. >>> >>> Another option is to trap a blocking WFE and offer the opportunity >>> to the scheduler to switch to another task, potentially giving the >>> vcpu holding the spinlock a chance to run sooner. >>> >> >> Idea looks to be correct from my experiments on x86. It does bring some >> percentage of benefits in overcommitted guests. Infact, >> >> https://lkml.org/lkml/2013/7/22/41 tries to do the same thing for x86. >> (this results in using ple handler heuristics in vcpu_block pach). > > What about the adverse effect in the non-overcommitted case? > Ideally is should fail to schedule any other task and comeback to halt loop. This should not hurt AFAICS. But I agree that, numbers needed to support this argument. For x86, I had seen no side effects with the experiments. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
